1. Field of the Invention
This invention relates generally to steerable, ground engaging wheeled assemblies for vehicles, and more particularly to steerable axle wheeled assemblies for drawn or trailed vehicles which are provided with wheel turn angle and direction indicator means and which are affixed to the vehicles in supporting relation; ample clearance between the axle and crop rows in the ground over which it is drawn being provided.
2. Description of the Prior Art
Various forms of wheeled assemblies with both steerable and non-steerable axles have been proposed and used in the prior art. In addition, some prior art steerable axle wheeled assemblies have been equipped with turn angle indicators. An example of a steerable wheel assembly for an automobile with turn angle indicator is disclosed in U.s. Pat. No. 1,166,680, issued Jan. 4, 1916, in which a turn indicator has a pointer in the form of an arrow fixedly mounted at the upper end of an upstanding rotary shaft which is pivotally attached via a rearwardly projecting crank arm connected to one end of a link. The link, at its opposite end, is pivoted to the steering rod of the front wheels of the automobile. When the steering wheel of the automobile is turned by the driver, the front wheels also turn, in parallel, and the pointer arrow pivots correspondingly to give an indication of the direction in which the wheels are headed. Such front wheel turn indicators have been found useful in automobiles in the past to provide the driver with information concerning the position of his front wheels. Such devices have the disadvantage however, of at least partially obstructing the driver's view in front resulting in an unsafe or hazardous driving condition. In addition, in automobiles, such appurtenances are, by present day standards of design, rather unsightly and aesthetically undesirable.
U.S. Pat. No. 3,103,909, issued on Sept. 17, 1968 discloses a turn indicator also intended for automobiles to indicate the turn angle or position of the front wheels when turning. This indicator operates through associated split gears on shafts and bearings when the steering wheel is turned on its shaft through the steering gear box of the automobile. The indicator also includes a pointer and gauge dial to provide information relative to turning angle and left or right direction of the front wheels. Such an arrangement has the disadvantage, however, of being unduly complex and mechanically complicated and impractical. In addition, such a device can provide front wheel turning angle information only because of its attachment to and dependence on the automobile's steering gear system. While overcoming the disadvantage of poor aesthetics which attended the previously described patented device, this device is too costly because of its relative complexity and mechanical impracticability to have application to implements and vehicles of the type with which the present invention is concerned.
U.S. Pat. No. 3,463,507, issued Aug. 26, 1969 discloses a dirigible wheeled assembly for a trailing or drawn vehicle in which a steering linkage is attached to a pair of wheels mounted for steering movement about their respective vertical axes. The assembly supports an agricultural implement such as a trailing plow and features a telescoping linkage or steering arm which permits the wheels to turn sharply without undue scuffing or dragging during the turn. However, this machine has the disadvantage that no means is provided whereby observation from the tractor will provide information as to the position of the trailing vehicle with respect to the crop rows in the terrain over which the vehicle is being drawn nor information as to the turn angle and direction of the wheels of the wheeled assembly with respect to the vehicle. Information of this sort is ordinarily very useful, desirable and important to an operator using these machines and implements. However, when operating them on hilly or contoured terrain without some means to tell the direction and turning angle or attitude of the wheels, it is almost impossible to keep the vehicle trailing along the intended course in the crop row.
Other prior art patents are known which disclose high clearance dirigible axles for wheeled assemblies, for example, U.S. Pat. No. 2,507,000, issued May 9, 1950. This patent discloses a front axle having a horizontal member and a pair of vertical members which are arranged to pivot about their long axes, when actuated through associated linkage members by action of an attached steering gear mechanism. The wheels are arranged on stub axles at the bottom of the vertical members and pivot therewith in a steering movement. Such an assembly is useful on a tractor which is moved over the ground in crop rows in planting fields and provides ample ground clearance above the ground. Such devices however, have the disadvantage that there is no indicator means to inform the operator of the direction or turning angle of the wheels during operation. Unless the assembly is used on a tractor, the wheels of which are visible to the operator, the latter has no way of knowing or determining the angular position of the front wheels when turning or when standing before the vehicle is put in motion.
In addition, since the wheeled assembly disclosed in this patent is intended for use as the front wheel assembly of a tractor, this patent does not address itself to the problem faced by the operator of a tractor which is drawing or trailing a wheeled vehicle in crop rows in the ground behind it, namely of obtaining, by observation, information as to the position of the trailing vehicle wheels with respect to the crop rows and/or other information as to the turn angle and direction of the wheels of the wheeled assembly with respect to the vehicle.
Another problem which attends wheeled assemblies of the prior art, both steerable and non-steerable, particularly when used with agricultural implements such as root plant crop harvesting machines, e.g., potato, onion and/or beet harvesting machines, windrowers and the like equipment used either in conjunction therewith, or independently thereof, concerns the location of the wheeled assembly axles. In the prior art, these axles are conventionally positioned and located on the trailing vehicle so as to pass transversely under or between the digger chains and conveyor belts and the like of the harvesting or windrowing machine vehicle and, as a result, an undesirable accumulation of dirt, debris and other materials such as plant vines and the like, occurs which means the machine must be stopped to clear away the offending material, thereby interfering with harvesting operations.